Carbonated beverages, such as soft drinks and beer, are commonly packaged in metallic containers such as aluminum cans. The carbonation within the beverage exerts pressure on the containers, thereby increasing the strength of the container walls. However, it is generally desirable to further strengthen the containers in order to decrease the likelihood of damage to the containers as well as minimize the necessary thickness of the container walls.
One method used for strengthening containers is to deposit a liquefied gas such as nitrogen onto the beverage immediately prior to sealing the container. After sealing, the evaporated liquefied gas creates pressure within the container and also displaces oxygen from the headspace, thereby helping to prevent spoilage of the beverage. Many devices used to accomplish this result simply lay the liquefied gas onto the surface of the beverage, rather than forcibly injecting the liquefied gas into the beverage. This may suffice for non-carbonated beverages as well as some carbonated beverages. However, with a carbonated beverage such as beer that tends to produce a frothy head upon filling the container, liquefied gas deposited within the container tends to roll off the frothy head of the beverage and out of the container.
One solution would be to forcibly inject a liquefied gas such as nitrogen into the beverage utilizing a high-performance, quick-responding solenoid. However, due to the extremely cold temperatures involved in utilizing liquefied gas, a solenoid-controlled injector system must be carefully designed to avoid atomization of the liquid, which may occur when the liquefied gas is not properly passed through various inlets and/or outlets within the system. Furthermore, the pressure within the system must be carefully controlled in order to deliver a consistent amount of liquid nitrogen to each container in a high-speed filling operation.